Artificial photosynthetic solar‐to‐chemical cycles enable an entire environment to operate in a more complex, yet effective, way to perform natural photosynthesis. However, such artificial systems suffer from a lack of well‐established photocatalysts with the ability to harvest the solar spectrum and rich catalytic active‐site density. Benefiting from extensive experimental and theoretical investigations, this bottleneck may be overcome by devising a photocatalytic platform based on metal sulfides with predominant electronic, physical, and chemical properties. These tunable properties can endow them with abundant active sites, favorable light utilization, and expedited charge transportation for solar‐to‐chemical conversion. Here, it is described how some vital lessons extracted from previous investigations are employed to promote the further development of metal sulfides for artificial photosynthesis, including water splitting, CO2 reduction, N2 reduction, and pollutant removal. Their functions, properties, synthetic strategies, emerging issues, design principles, and intrinsic functional mechanisms for photocatalytic redox reactions are discussed in detail. Finally, the associated challenges and prospects for the utilization of metal sulfides are highlighted and future development trends in photocatalysis are envisioned.

Recent Progress of Metal Sulfide Photocatalysts for Solar Energy Conversion

Graphdiyne (g-CnH2n-2) is a new carbon material composed of sp and sp2 hybrid carbon atoms. Since the synthesis by Li's team, graphdiyne has been widely studied in other fields because of its excellent properties. In this paper, graphdiyne was synthesized from copper-containing materials and the composite GDY/CuI/MIL-53(Al) S-scheme heterojunction is prepared for photocatalytic cracking of water to produce hydrogen. First, GDY/CuI was prepared by organic synthesis, and then GDY/CuI was anchored on the surface of MIL-53(Al) by in situ ultrasonic stirring. After the continuous optimization of experimental conditions, the final hydrogen evolution rate is much higher than that of MIL-53(Al). This efficient photocatalytic performance can be attributed to the S-scheme heterojunction formed by the unique energy band arrangement. At the same time, the mechanism of charge transfer was demonstrated by in situ irradiation X-ray photoelectron spectroscopy. The strong interaction among the three strongly promotes the separation and transfer of photogenerated electron-hole pairs.

Graphdiyne (CnH2n-2)-Based GDY/CuI/MIL-53(Al) S-Scheme Heterojunction for Efficient Hydrogen Evolution.

Defected tungsten disulfide decorated CdS nanorods with covalent heterointerfaces for boosted photocatalytic H2 generation.

The rational design of hierarchical In2O3/MIIIn2S4 (MII: Ca, Mn, and Zn) hollow tubular (HT) heterostructures was successfully performed by the preferential growth of ternary metal sulfide (MIIIn2S4) two-dimensional (2D) nanosheets on MIL-68(In) metal–organic framework (MOF) derived hollow tubular In2O3 using a facile low-temperature reflux reaction. The efficiency of HT-In2O3/MIIIn2S4 binary heterojunctions was studied for the photocatalytic activation of small atmospheric molecules. The ultrafast interfacial charge migration, better photoexcited charge separation, and significantly improved photocatalytic H2, NH3, and H2O2 production could be attributed to the narrow band gap energy of the MIIIn2S4 and S-scheme electron migration mechanism between In2O3 and MIIIn2S4 components in the heterostructures. Thanks to its structural and compositional advantages, the optimal HT-In2O3/MIIIn2S4 (1:1) heterostructure photocatalysts exhibited outstanding photocatalytic hydrogen evolution reaction and nitrogen and oxygen reduction reaction activity under visible-light illumination. Among the HT-In2O3/MIIIn2S4 (1:1) hetrostructures, the HT-In2O3/ZnIn2S4 (1:1) photocatalyst displayed the highest H2, NH3, and H2O2 generation (5331, 870, and 5716 μmol g–1 h–1) with conversion efficiency of 34%, 6.5%, and 0.291%, respectively. This study offers a comprehensive analysis on how the coupling of three different d0, d5, and d10 ternary metal chalcogenides MIIIn2S4 with HT-In2O3 affects the photocatalytic H2, NH3, and H2O2 production. 

MOF-Derived Hollow Tubular In2O3/MIIIn2S4 (MII: Ca, Mn, and Zn) Heterostructures: Synergetic Charge-Transfer Mechanism and Excellent Photocatalytic Performance to Boost Activation of Small Atmospheric Molecules

Rational construction of S-scheme BN/MXene/ZnIn2S4 heterojunction with interface engineering for efficient photocatalytic hydrogen production and chlorophenols degradation

Sandwich-like P-doped h-BN/ZnIn2S4 nanocomposite with direct Z-scheme heterojunction for efficient photocatalytic H2 and H2O2 evolution

Photocatalyst TiO2/SO42- nanoparticles were synthesized by sol-gel method via hydrolysis of pure titanium isopropoxide in n-propanol and acetylacetone solution. The hydrolysis rate and condensation rate of titanium isopropoxide were controlled by concentrated sulfuric acid. Its catalytic activities on the photo-degradation of acid red 18 which is acid azo dyes were studied experimentally and theoretically. The catalysts were characterized by XRD (X-ray diffraction), IR (infrared radiation), BET surface area and SEM (scanning electron microscope). The effects of various catalytic degradation factors of nanocrystalline TiO2/SO42- were discussed in the present paper, which included solution pH, initial concentration of acid red 18, UV irradiation time and the reaction temperature. The results showed that the photo-catalytic activity of this material was obvious signiﬁcantly when pH is 7.0; degradation temperature is 25 °C and irradiation time is 90 minutes for different concentration acid red 18 solutions.

Photo-Degradation of Acid Red 18 by Using TiO2/SO42- Nanoparticles under UV Light

Using photocatalytic hydrogen evolution (PHE) technology is a powerful way to solve the energy shortage. In this study, a hexagonal hollow tubular nitrogen-doped carbon (N−C)-coated In2O3/CdZnS heterojunction photocatalyst was in situ synthesized using a simple oil bath heating method. Results show that the PHE rate of N−C/In2O3/CdZnS (∼22.87 µmol h−1) is ∼2.4 times that of pristine CdZnS (∼9.49 µmol h−1) and ∼54.5 times that of pristine In2O3 (∼0.42 µmol h−1). After four cycles, the PHE rate can still retain more than 90% of the original. Its excellent photocatalytic performance is mainly attributed to the following aspects: (1) the N−C layer acts as an electron transport bridge, which ensures the efficient electron transfer of the photocatalytic reaction; (2) the hollow tubular structure enhances the light reflection and absorption; (3) the N−C/In2O3/CdZnS heterostructure improves the carrier recombination and photocorrosion; (4) the large specific surface area and mesoporous structure provide a large number of reactive sites. This study provides a novel idea for designing visible-light-type heterojunction catalysts. 

/pdf/metal-organic-framework-derived-nitrogen-doped-carbon-coated-g4rg7xu6.pdf

Metal-organic framework-derived nitrogen-doped carbon-coated hollow tubular In2O3/CdZnS heterojunction for efficient photocatalytic hydrogen evolution

Different types of natural K+ channels share similar core modules and cation permeability characteristics. In this study, we have developed novel artificial K+ channels by rebuilding the core modules of natural K+ channels in artificial systems. All the channels displayed high selectivity for K+ over Na+ and exhibited a selectivity sequence of K+ ≈ Rb+ during the transport process, which is highly consistent with the cation permeability characteristics of natural K+ channels. More importantly, these artificial channels could be efficiently inserted into cell membranes and mediate the transmembrane transport of K+, disrupting the cellular K+ homeostasis and eventually triggering the apoptosis of cells. These findings demonstrate that, by rebuilding the core modules of natural K+ channels in artificial systems, the structures, transport behaviors, and physiological functions of natural K+ channels can be mimicked in synthetic channels.

Shou Heng Zhang

Papers

Sandwich-like P-doped h-BN/ZnIn2S4 nanocomposite with direct Z-scheme heterojunction for efficient photocatalytic H2 and H2O2 evolution

Photo-Degradation of Acid Red 18 by Using TiO2/SO42- Nanoparticles under UV Light

Metal-organic framework-derived nitrogen-doped carbon-coated hollow tubular In2O3/CdZnS heterojunction for efficient photocatalytic hydrogen evolution

Synthetic K+ Channels Constructed by Rebuilding the Core Modules of Natural K+ Channels in an Artificial System.

Bioinspired fabrics with single fiber as ultra-sensitive acoustic sensor